Bessemerizing iron



40 .the acid slag formed in the process.

UNITED sTATEs PATENT ornicn. f

RICHARD S. MoCAFFERY,' 0F MADISON, WISCONSIN..

BESSEMERIZING- IRON.

Specification of Letters Patent. Patented API'. 27, 1920.

Application filed November 13, 1918. Serial No. 262,272.

To @ZZ whom t may concern Be it known that I, RICHARD S. MoCAr- FERY, a citizen of the United States, residing at Madison, in the county of Dane, State of lisconsin, have invented certain new and useful Improvements in Bessemerizing Iron;

and l do hereby declare the following to be a full, clear, and exact description of the invention, such as will enableothers skilled 1c in the art to which it appertains to make and use the same.

This invention relates to the bessemerizing lof iron, and has for its object the provision of certain improvements in the acid 1'5" process of bessemerizing.

The acid Bessemer process is now carried out in an acid (silicious lined) converter, with an acid (silicious, or' aluminous, or both) bottomthrough which the air blast is introduced by twyers', to oxidize the charge ofv pig iron, which, in general, is essentially carbon-, manganese, silicondoearing iron. The accepted theory is that a siliciousslagrl is formed; and the linings of the ybottom and lside Walls ofl the converter arel made acid to resist the corrosion of this acid slag.'v Even when formed of acid materlals, the bottom lining ofthe 4converter is, in practice, rap-idly corroded, and wears away much faster than the side-wall lining,

v and it is on this account that itis customary in converter construction to make the entire bottom ot the converter removable, so that a bottom with a badly corroded lining may be quickly replaced by a. new one.

"The corrosion or rapid wearingaway lof the bottom liningr of the converter, in the acid .Bessemer process, has heretofore been attributed to the interaction therewith of The acid slag, however, floats onl the top of .the molten metal and comes in contact with the bottom lining' to a very limited extent during the blow. Furthermore` the acid '45 lining on the side Walls of the converter.

with which the acid slag: is in close contact. is corroded toa much less extent than the bottom lining. It is conceived .by me that the" rapid corroding of the bottom lining is *5c due `tov other agencies than the acid. slag as follows l *The air blown into the converter unites immediately with the iron 4and manganese of the molten bath to formoxidsof. iron and '55 manganese. These oxids react on the silicon;

carbon, etc., present in the molten bath and oxidize these latter substances. The silica which is thus formed by the oxidation of t e silicon combines with the oxids of iron an I manganese to torni silicate slags which are generally quite acid in character and Hoat on the bath.k However, the molten bathiti self, in contact with the bottom of the coliverter, contains oxids of iron and manganese which are basic. Such basic materials contained in the molten bath itself will react with an acid lining and lcorrode'the same. The present invention is based on the dis' covery that it is such basic products, formed in the molten bath during the bessemerizing', which react onv the present 'acid bottoms of the converters and rapidly corrode them.

The present invention comprises carrying out the bessemerizing of cast or pig iron under acid slag-forming conditions in a converter.havingin part, al non-acid lining. The non-acid part of the lining vmay be formed of basic refractory materials, such, `for example, as magnesite; dolomite,`.lime, oxid of iron, zirconia. and the like, or of neutral refractory materials, such, for example, as chromite, bauxite, andthe like.

tures ot' suchmaterials. ot which the said liningr is made, in accordance with the principles of the present invention.

The invention, accordingly, involves the carrying,` out of the acid Bessemer process in a converter having' a' non-acid lining for such parts thereof as the aforementioned basic products come in active or intimate. contact with. Generally, the inve-ntioncontemplates the provision of a non-acid lining* for those parts of thecon'verter which.

the resent da Y ractice otlinino converters'.

with acid material. are nlnst.,rapidly lcor-.1 rode'd.' The `corrosion ofthe '(acid) con-:e verter liningis mostrapid where the oxygen offy the blast comes' in contact with the molten iron andfoxidizes the iron and mang'anese. Generally speaking, this is .right in liront of the twyers. `Thns, in' accordance with the principles ot the presentinvention, the' tWyer region o tw len-.zone of the -.con-v verter-.js provided, tf a;.. .nonacid lining, and such non-acid lining may, if desired,

4either the bottom-blown type or the side- 5G- blow. However, the principal advantages of the invention are obtained by carrying out the acid Bessemer process in a converter having a nonacid lining for such parts thereof as lcome in intimate contact with the basic products present in the molten fmetal', and I do not desire or intend to limit the invention to the provision of a non-acid lining for every part of the converter with which the aforementioned basic products might perhaps come' in contact', since the broad aim of the linvention is to reduce the corrosion which results from the present day practice of carrying out the acid Bessemer process in an acid llined .converter,and an effective reduction of the corrosion can be brought about by lining with non-acid material those partsI` of the converter which have heretofore been most rapidly corroded.

As'hereinbefore pointed out, the acid Bessemer process, asv now practised, is carried out in a converter havingA an acid lining, usually a silicious lining. The present invention contemplates no change in the character of those portions of the converters lining which .come in contact with the acid slag. Suchvportions of. the lining must be composed of acid materials7 for reasons well recognized in the art.

The non-acid lining, providedv in accord- -ance with the present invention, may be made up of neutral refractory material, or of basic refractory material, or a mixture ofneutral and basic materials, held together by suitable binding agents, as previously stated. Since it is usually not advisable to -have a basic lining in contact with an acid lining in any furnace subjected to high temperatures, I prefer, where a' basic lining, or a non-acid lining containing basic material` is provided, in accordance with the present invention, to separate the basic lining from the acid. lining, provided to resist the action of the acid slag, by the interposition of a zone of neutral refractory lining.

The -:invention is equally applicable to blow-n type of converter, and, in fact, to any type of converter in 'which an air blast is blown through a body of molten iron.

In the case of a bottom-blown converter, the twyer region' comprises substantially the bottoni of the converter. hen bessemer izing in this type of converter, the principal advantages resulting from the practice of the present invention are obtained by carrying out the acid Bessemer process in a converter, whose bottom only is lined with nonacid material.. However, it is to be understood that the invention also contemplates the provision' of a non-acid lining' vfor such `.portions of the side wall of theconverter as maybe subjected to the action of the basic has an acid lining A.

Fig. 1 diagrammatically represents a bot-.

tom blown converter in which the bottom or twyer region of the converter has basic lining B', while the body of the converter In the vconverter represented in Fig. 2, .the basic lining B 4 extends upwardly a short distance from the bottom and is separated-from the acid bodyv lining A by an intermediate lining N of neutral refractory material. In the con verterl of Fig. 3, all that partef the con-l verter in contact with molten metal during the blow is of basic refractory material.

This converter thus has a basic bottom lining B, and a basic side wall lining B3 conforming approximately in height to the normal depth of the molten metal duringthe blow. The remaining body portionof this converter has an acid lining A3. In the converter.` of Fig. 4, the side wall lining N4,

approximately conforming in height to the normal depth of the metal during the blow is of neutra-l refractory material and is'intermediate the acid body lining' A,L and the basic bottom lining B4: In the converters of Figs. l and :2, the twyers are separate-ly `formed and the lining made byramming the basic refractory material around them, while in the converters of Figs. 3 and 4:, the twyers are formed in the lining itself.

Figs. 5 and 6 diagrammatically illustrate side blown converters. As shown in Figli, the bottom and. sides of the converter in contact with the molten metal during the conditions, but, on the'contrary,j the inventionis concerned specifically with bessemenizing under condi-tions i which produce an acid slag,-the so-calledV acidprocess.' I 'do not, therefore, claim generally the useof a neutral. orbasic lining, but rather the carryblow are lined withliasic material BG, while the remaining body portion of the converter iis.

ingoutvof the acid Bessemer process-in a converter Whose tivyeixregion, or'tliose parts of which are in Contact with the molten y ,metal during' the blow, are lined withl nonvk described. y A 2. The processl of refiningvirn Which coml I'claim:v l A. y .1. vThe process of refining iron `'vv'ln'ch comprises. bessenierizing a loathof molten inetal, withou'tfbasic additionsin a con cid material, as more particularly set forth in the appended claims.

acid lining-,'e'iicept-for .such parts thereof as come in; contact` with the basic products `ivliicli may be liberated during thebessemerizing process,'s'aid parts having anon-acid lining containing basic material and 'a lining ofl neutral materiall intermediate said -nonhaving an acid lining, except in its twyer reverterprovided Witli an acid lining, except in the region contacting'Wit/li the basic products which inay'beliberated during the per- .foi-mance prises besseineriz'ingv a bath of molten metal ,under acid'slag-forming conditions in a converter providedwitli 'an acid lining, except.

in tlieregion contacting with the basic prod` iicts 'Wliich'niay beglibe'rated during the perl formance of lthe process; substantially. as described.' i i 3. A converter forbes'semerizing iron un dei vacid slag-forming conditions having anA lacid lining,'e.'xcept for s'iich pai-ts .thereof as comev in contact with the .basic products which in'ayV be liberated during the' bessemerizingzpi'ocess; substantially as described;

4'. A coni'ie'rter for besseinerizing iron -under acid slag-forming conditions having an acid lining, except for such parts thereof as come .incontact with the basic products vof the process; substantially as` acid-lining. and said vacid lining; substantially described. )v

l. A converter for bessernerizing iron *and said acid linings; substantially as 'de-y` I '9. A converterfor bessenieri'zi'ng iron having tivyeis in the body structure thereof with the vtwyfer `ref ion lined With non-acid which may be liberated during the' bessenier- .icing process, said parts having a non-acid lining containing basic material; substantially as described.v

AI converter for bessein'erizing iron uny deracid slag-forming' conditions having an acid lining, exceptfor sucli parts thereof as [come incontact With the basic; products V which niay be liberated duringthe besseinei'- izing process, said parts having a non-acid lining inade up of basic and neutral refractoiyniaterials held togetherV by a'binding agent; 'sui'istantially as describe G..A coni/'ertervfor bess'einerizing iron iin der-acid slag-forming conditions having an yrefractory material' and side Walls lined in .whole or in part lv'vithacid refractory material; substantially as described.

10.. converter' for bessemerizing iron having tyvyers in the body structure thereof with tlie-twyer region lined With basic re-V fractory material and side. ivalls lined in Whole'ror in part with acid refractory' material; substantially as described.

"11. A converter for besseniei'izing iron having its tivyer region lined with non-acid refr'actory material'aiidside Walls lined in part with acid refractory-niaterial, and a' n oivacid refractory lining intermediate said non-acid lining` and said acid side Wall lining; substantially as' described.

12. A converter for. besseinerizing ironv having .its tWye'r region lined with basic refractory material and side Walls having an .Lipper lining of acid refractory material and.

'a lining of neutral refractory material inter-A mediate said basic lining and said upper'acid lining; substantially as described. ln testimony whereof I aiiix'my signature. RICHARD S.. MCCAFFERY.

for besseiiierizngfi'ron'iV 

